The Duracell Powermat GoPower Overnighter Backup Battery (Black) allows you to take charge of your power needs. This universal 4400mAh battery with an output of up to 2.1A allows you to charge your phone and tablet with a single charge. Simply attach your device to the Overnighter with a USB cable, press the copper button and watch your device begin to charge. Due to its compact size the Overnight is easily carried and ideal for the on the go individual who may need to charge their device more than once. The Overnighter can be recharged by connecting it to a USB power source, or by using any Duracell Powermat charging surface or PMA compatible surface.